Are you primarily concerned with the scheduled conference statistics at the top of the stats & reports page (which are able to be viewed online as well), or the report functionality? Since the reports are maintained as plugins, it should be (relatively) easy to tweak them according to personal needs, or even create new ones. The statistics stuff at top, however, was ported directly from OJS 2 I believe, and perhaps could be better rethought in terms of how it relates to OCS.
What would you think about being able to view stats per year and per scheduled conference side-by-side? I think the more useful numbers in this case would be the by-conference ones -- you'd be able to see # of registrants per scheduled conference; # of submissions vs. acceptances; etc. The per-year numbers would still likely be useful, at least in some cases, but I do agree that it would be good to have both.